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Title: Waste water heat recovery apparatus

Patent ·
OSTI ID:6716737

Waste water heat transfer apparatus is disclosed in which the waste hot water from residential or commercial uses such as washing, etc., is passed into a separate drain and thence into a heat exchanger which includes a waste water conduit therein, and thence to the sewer drain. A supply water conduit extends through the heat exchanger generally paralleling the waste water conduit and has fresh water run therethrough in a direction opposite to that of the flow of waste water to an outlet end, after which the supply water is provided to a water heater. The heat exchanger interior is filled with a heat transfer liquid, and is so divided by baffles that a temperature gradient is formed in the heat transfer liquid adjacent to the waste water conduit, with the liquid being warmest adjacent the inlet of the waste water conduit and decreasing in temperature toward the outlet of the conduit. The supply water, flowing in the opposite direction to that of the waste water, has its lowest temperature at its inlet end, which is adjacent the lowest temperature heat transfer liquid, and encounters progressively warmer adjacent heat transfer liquid as it rises upwardly in the heat exchanger toward its outlet end. A substantially constant temperature differential is thereby maintained throughout the heat exchanger between the waste water within the waste water conduit and the adjacent heat transfer liquid, and between the supply water in the supply water conduit and the adjacent heat transfer liquid. The transfer of a portion of the heat contained in the waste water to the supply water reduces the amount of energy that must be consumed by the water heater, and the system may also be tied to a hot water space heater for a home or other building to preheat the water supplied to the boiler and thereby reduce the energy demand for space heating purposes.

Assignee:
EDB-83-016962
Patent Number(s):
US 4341263
OSTI ID:
6716737
Resource Relation:
Patent File Date: Filed date 3 Nov 1980; Other Information: PAT-APPL-203718
Country of Publication:
United States
Language:
English